NASET News Alert

More Than Half of Severe Mental Disability Cases Not Inherited: Study

October 02, 2012

More than half of the cases of severe intellectual disability are the result of random genetic mutations that are not passed down from parents, researchers from Switzerland and Germany report. Severe intellectual disability, also known as nonsyndromic mental retardation, is the most common form of mental retardation. Children or adults with the condition have no physical abnormalities, but have IQs of less than 50. It affects up to 2 percent of kids worldwide. The new study, which appears online Sept. 27 in The Lancet, suggests that many of the gene variants associated with the condition show up for the first time in the affected children. To read more, click here